The present invention relates to a character recognition apparatus which recognizes the types of newspapers, magazine or the like, and the hand-written characters so as to convert them into the character codes.
Conventionally, in a character recognition apparatus, a system is adopted for extracting the recognition object character from the image data inputted from a scanner or the like, and obtaining the features of the recognition object character, and obtaining the distance between the features of a recognition candidate character group registered in advance and the features of the recognition object character so as to have, as a recognition result, the closest character from among the recognition candidate character group.
The construction of the conventional example is shown in FIG. 11. The picture image provided through the scanning of the manuscript from the scanner 21, which is also referred to as an image input portion, is stored in the picture image memory portion 22. In the character extracting portion 23, the recognition object character pattern is extracted as a rectangle from the picture image data stored in the picture image memory portion 22. In the direction code designating portion 24, when the polarity of the picture element point of the recognition object character pattern is different from the polarity of at least one of eight picture points adjacent to the picture element point, the picture element point is considered as a boundary point, and the direction code of the boundary point 11 is determined through its relationship with the picture element point adjacent to such a boundary point 11 as shown in FIG. 2(b), the number of the boundary points corresponding to each direction code is obtained as the features showing the boundary direction density of the character.
In the recognition portion 25, the distance between the features of the recognition object character obtained by the direction code granting portion 24 and the features of the recognition candidate character group registered in advance in the dictionary 26 is calculated, and the character closest in the distance in the recognition candidate character group is the recognition result.
In the conventional example, the boundary direction density of the recognition object character " " shown in FIG. 7(a) and the boundary direction density of the recognition object character " " shown in FIG. 7(b) agree as in FIG. 12 so as to cause an erroneous recognition.